Here is a question for you; some of you might relate to it instantly, while others might take a while to ponder, because the topic is so basic. It is OK to be on either side. The key thing is to think about it.

What questions keep you awake at night?

For most of us, it is our everyday affairs that we ponder about before going off to sleep. What did we do during the day? What might we want to do in the coming days? How will I do on my midterm tomorrow? Am I going to get that promotion I always wanted? But, what do people at the frontier of science spend their nights thinking about? What questions keep them awake at night? That was the question posed to nine eminent physicists at the Quantum to Cosmos —in short— Q2C Festival: Ideas for the Future. This event was organized by the Perimeter Institute for Theoretical Physics and was held here in Waterloo, Ontario. The discussion was moderated by prominent science journalist Wilson De Silva, editor for Cosmos Magazine.

What question about physics keeps you awake at night?

Sean M. Carroll, Senior Research Associate at the California Institute of Technology and author of “From Eternity to Here,” claims he sleeps pretty soundly at night. One question, though, used to bother him in his younger days: “What if the universe didn't exist?” He does not know the answer to that question yet. Nowadays he ponders why the laws of physics are the way they are in this universe. Why these particular laws rather than other laws? Again, there is no straight forward answer to that question, because it is still too big a question to answer, given our current knowledge. Carroll is optimistic and imagines that one day we will know the answer to such a question. Some say that these laws are unique and this is the only way we can have them, but Carroll suspects we have a choice in these laws. Maybe there are different universes and we happen to be in a particular version with these specific laws.

Katherine Freese, the George Eugene Uhlenbeck Professor of Physics at the University of Michigan and the Associate Director of the Michigan Center for Theoretical Physics admits that she has been more of an insomniac in contrast to Sean M. Carroll. She is also excited, because she expects a breakthrough in the question she has been working on for the past 20 years: “What is the universe made of?” Most people like us know that the world around us is made up of atoms. But the amazing thing we do not know is that atoms make up only four per cent of the universe. What about the rest? 25 per cent is made up of dark matter and finally the rest is dark energy. Entire galaxies are made of dark matter. Our own galaxy, the Milky Way, is enveloped by an enormous spherical globe of dark matter.

So what is that dark matter?

Of two school of thoughts, the WIMPs, or Weakly Interacting Mass of Particles have gained more acceptance in the community. Satellites equipped to detect these particles are now showing strong evidence of the presence of WIMPs. So, what keeps her up is the thought ”Are these things for real?”

On the other hand, Leo Kadanoff, a professor emeritus of the University of Chicago and a past President of the American Physical Society (APS), insists that he sleeps like a baby. He ponders though, how physicists like him can most effectively help society and the world around them. These complexities arise from simple laws of physics working themselves out. “The same laws that apply on the scale of an apple also apply on the scale of the moon,” says Kadanoff, and he also studies these same laws acting on different scales.

Lawrence Krauss is an internationally known theoretical physicist and author of several bestselling books including “The Physics of Star Trek.” He is delighted at the progress that has been made in the realm of physics, but he worries whether we have come to the limits of empirical science. He claims that one universe might not be enough to answer all our questions. He thinks that we will have to be using more theory to answer our question rather than experimental data and that is what he is afraid of. One of the biggest misconceptions of science is that it tells the truth, when in actuality science rules out what is false. Not being able to falsify something concerns Krauss.

Gino Segrè is a professor of Physics and Astronomy at the University of Pennsylvania. He wonders how to get to another universe and thinks that the Ministry of Tourism might be very interested in the answer to that question. He says that Newton was 25 when the apple supposedly fell on his head causing him to think about the laws of gravity. Einstein was 25 when he thought about relativity. Many other scientists who have made crucial discoveries were also very young. Segrè thinks that the next great discovery might be made by another 23, 24 or 25 year old who will come and say “You are all wrong, this is the way it is.” He pleas to the youngsters in the audience to think crazy ideas, wild ideas. He lies awake at night thinking “What is the craziest thing I can think of” and then falls asleep.

David Tong is a theoretical physicist at the University of Cambridge. He spends a lot of his time on string theory and that, he says, used to keep him up at night. People say that string theory is a theory of everything and will do a lot for physics, he says, which he thinks is a very beautiful theory. Unfortunately, we might never know if the string theory is right or rather whether it is wrong. What helps him sleep now is the thought that String theory is a useful theory and can be applied to different situations.

Neil Turok is the Director of Perimeter Institute for Theoretical Physics. He does not share pessimism toward physics future. “We are absolutely blessed,” he says, and he didn't imagine what was coming when he started his journey in cosmology. We have mapped the whole universe and learned so much. What keeps him awake at night is wondering about the singularity of the big bang from which everything has come to be. Another thing that he ponders over is how are we going to take advantage of the new communication, the web and the fact that the world is one community.

Andrew White is a professor of physics at the University of Queensland, Australia and the Director of the Quantum Technology Laboratory. He claims that what has been keeping him awake at night for a long time is his son's wet nappies. But aside from that, when he gets time off, he thinks about a very old question in the world of physics “what is life and what is the impact of the recent second quantum revolution on life?” In particular, he deals with the phenomena of correlation and entanglement which Einstein called “spooky action at a distance”. This phenomenon is used in quantum computing, but what is incredible is that living things in nature have been exploiting the phenomenon of correlation for a long time.

Anton Zeilinger is a professor of physics at the University of Vienna and the Director of the Institute for Quantum Optics and Quantum Information at the Austrian Academy of Sciences. He thinks about how far are we along the road in the world of science. He thinks that we are far from understanding everything. “We have just scratched the surface,” he says. He gave a simple example of the phenomena of entanglement. If you had two quantum entangled die and you threw one die here and another die somewhere else, they would always show the same number. This is something completely random, Nothing is telling the die what to do. What do we really describe in physics? Is it really out there? Or is our observation giving us a compromised reality? What is reality then?

These stories give us a firsthand look at what goes on in the minds of physicists in today's world. A unifying theme can be seen, a quest to answer the questions that tell us the story of the universe — how it began, how it will end, and all that is in between. Some questions are very fundamental, while others shake the very notion we all have about the universe. Reality or not, we, the ordinary folk, must also observe the workings of the universe and ask questions, like how and why are we here. Next time you go to sleep, what will you think about? If you want to learn more about what happened at the Q2C festival visitt www.q2cfestival.com.